Match the reactions in Column-$I$ with their products in Column-$II$.
| Column-$I$ (Reagents) | Column-$II$ (Product) |
| :--- | :--- |
| $(A) \ CH_3CHO + 2C_2H_5OH \xrightarrow{HCl_{(g)}} $ | $(i) \ (CH_3)_2C(OCH_2)_2$ |
| $(B) \ CH_3COCH_3 + CH_2OH-CH_2OH \xrightarrow{HCl_{(g)}} $ | $(ii) \ CH_3CH(OH)CN$ |
| $(C) \ CH_3CHO + HCN$ $\xrightarrow{OH^-}$ $\xrightarrow{H_3O^+}$ | $(iii) \ CH_3CH(OC_2H_5)_2$ |
| $(D) \ CH_3CHO + HCN \xrightarrow{OH^-} $ | $(iv) \ CH_3CH(OH)COOH$ |

(A-III, B-I, C-IV, D-II) The reactions are analyzed as follows:
$(A)$ Acetaldehyde reacts with ethanol in the presence of dry $HCl$ gas to form an acetal: $CH_3CHO + 2C_2H_5OH \xrightarrow{HCl_{(g)}} CH_3CH(OC_2H_5)_2 + H_2O$. This matches $(iii)$.
$(B)$ Acetone reacts with ethylene glycol in the presence of dry $HCl$ gas to form a cyclic ketal: $CH_3COCH_3 + HOCH_2CH_2OH \xrightarrow{HCl_{(g)}} (CH_3)_2C(OCH_2)_2 + H_2O$. This matches $(i)$.
$(C)$ Acetaldehyde reacts with $HCN$ to form a cyanohydrin,which upon acid hydrolysis yields a hydroxy acid: $CH_3CHO + HCN$ $\xrightarrow{OH^-} CH_3CH(OH)CN$ $\xrightarrow{H_3O^+} CH_3CH(OH)COOH$. This matches $(iv)$.
$(D)$ Acetaldehyde reacts with $HCN$ to form a cyanohydrin: $CH_3CHO + HCN \xrightarrow{OH^-} CH_3CH(OH)CN$. This matches $(ii)$.
Therefore,the correct matching is: $A-iii, B-i, C-iv, D-ii$.